Mechanical stoker.



No. 704,880. Patented m 15, 1902. a. HOWARD & a. mass.

MECHANICAL STOKER.

(Application filed Ian. 18, 1902.)

2 Sheets-Sheet 2.

(No MoqeL UNITED STATES PATENT OFFICE.

GEOFFREY HOWARD AND GEORGE GIBBS, OF BEDFORD, ENGLAND.

MECHANICAL ST'OKER.

srncrrxcarron forming part of Letters Patent No. 704,880, dated July 1 5, 1902.

7 Application filed January 18,1902. Serial No. 90366, No model-I1 T aZZ whom it ntay concern;

Be it known that we, GEOFFREY HOWARD and GEORGE GIBBS, engineers, subjects of the kind of such stokers wherein the fuel falls from a hopper into a chamber in front of a ram or pusher'which, by steam or other fluid under pressure acting on a piston connected with the ram or pusher, is caused to thrust I the fuel into a retort or combustion-chamber 3 said piston works by a valve actuated by the attendant at the times the fuel is 'required'to be supplied to the furnace. The chief object of our invention is to provide a contrivance in connection with the. said valve whereby the latter will be "auto-f matically or mechanically actuated at the proper times without manual assistance, said contrivance being capable of adjustment so as to supply the fuel at periodical intervals, which can be prolonged or diminished in accordance with requirements. The said contrivance is preferably adapted to cause the ram or pusher to retire immediately after fully completing its feed-stroke and to remain stationary in its retired position until required to perform another feed-stroke.

The said contrivance is also preferably adapted to so actuate the said valve that it will cut ofi the steam at anydesired part of the stroke of the piston and enable a cushioning effect to be obtained for preventing shock or concussion at the termination of the stroke in either direction.

In order that our said invention may be clearly understood and readily carried into efiect, we will proceed to describe the same more fully, with reference to the accompanying drawings, in which- Figure 1 is aside elevation of apparatus constructed in accordance with our invene tion. Fig. 2 is a plan of the same, and Fig.

3 a crosssection on the line 1 1 of Fig. 1.

.Fig. 4: is a side elevation of a modified form of the apparatus.

Fig. 5 is a plan of the same, and Fig. 6 a cross-section on the line 2 2 of Fig. 4.

In all the figures like letters of reference indicate similar parts.

A is the steam or other fluid pressure cylinder.

. B is the piston, and B the piston-rod.

C is the slide-valve.

D is the ram or pusher, and D the chamber in which'it Works.

E is the hopper from which the fuel is supplied to the chamber D.

F is the retort forming part of the furnace into which the fuel supplied to said chamber D. 'is thrust by the said ram or pusher.

Referring more particularly to Figs. 1 to 3, G G G? G are a train of gear-wheels loosely mounted on studs G, projecting from the side of the chamber D and adapted to receive an intermittent motion from an oscillatory arm g, provided with a spring-pawl g, engaging with the teeth of the gear-wheel G. Connected with this arm 9 is a rod 9 which re- 1 ceives a vertical reciprocating movement in any suitable mannersuch as, for instance, from some moving part actuated by its own motive power or by the engine or apparatus used for supplying the forced draft which is necessary with this kind of mechanicallystoked furnace. The stem 0 of the slidevalve O is furnished with a sliding bar 0, which is slotted at c a, so as to engage with the studs G, about which the aforesaid gearwheels revolve, these slots and studs acting as guides for the sliding bar. The said bar is provided with a transverse pin or roller 0, which engages with a cam-groove 9?, formed in the adjacent faceof the gear-wheel'g so that as the said gear-wheel revolves it imparts, through the transverse pin or roller 0 a rectilinear reciprocating motion to the bar 0 and the slide-valve O. The shape of the aforesaid cam-groove g is such thatthe slidevalve is shifted to cover and uncover the steam-ports of the working cylinder A, so that live steam is admitted first to one side and then to the other side.of the piston in accordance with the. desired working of the apparatus. In the position in which the parts are represented in Fig. 1 the cam-wheel G by revolving in the direction of the arrow, will cause the slide-valve to move first toward the left and admit live steam to the right-hand side of the piston, which, together with the ram D, will be forced toward the left, thereby introducing a charge of fuel into the retort F. The continued movement of the said cam-wheel G will then shift the said roller 0 toward the right, whereby the movement of the slide-valve will be reversed and will permit the steam on the right-hand side of the piston to be exhausted and live steam to be admitted to the left-hand side of the piston. The latter will be thus driven toward the right and the ram D retracted ready to perform a fresh. charging stroke. The further continued movement of the said cam-wheel G then shifts the said roller 0 toward the left, whereby the movement of the slide-valve will again be reversed to cut off the steamsupply to the cylinder A and permit the exhaust-steam to escape. The roller 0 will then lie in the concentric portion of the cam-groove g, and the slide-valve will consequently remain inactive until the irregular portion of the cam-groove again actuates said roller 0 in the manner above described.

In order to permit the steam to be cut off from the cylinder A at any desired part of the stroke of the piston, we provide the said ram with an arm d, which projects downwardly through an. opening in the lower part of the said casing D. This arm d is furnished with a lateral projection or roller d, which is adapted to strike against abutments d d as the said ram or pusher is completing either of its strokes. These abutments are secured to a sliding bar (1 by set-screws or other suitable means that will permit of the said abutments being adjusted or set on the said bar, so that the distance between them can be increased or diminished. This bar is carried by means of arms d d, loosely mounted on the studs G, about which the gear-wheels G G revolve, so that the said bar can thus perform a longitudinal reciprocating movement when the abutments are alternately struck by the aforesaid projection d of the arm d. Mounted near the lower ends of the said arms 01 d are pawls d (1 which by means of a spring (1 are caused to engage with the teeth of the said gear-wheels G G in opposite directions. When the bar 01 is shifted toward the right by the pin d, on the arm at striking the abutment d the pawl at will impart rotary movement to the gear-wheels G G, and when said bar (1 is shifted toward the left by the pin (1 striking the abutment d the pawl d will also impart a rotary movement to the gear-wheels G3 G It will therefore be seen that the cam-wheel G will receive, in addition to the movement transmitted to it from the oscillating arm 9 and the wheels G G G, a further movement as the ram and piston approach the ends of their forward and rearward strokes, and that the slide-valve will thus be shifted earlier or later in the stroke of said piston, according as the said abutments are set closer together or farther apart.

For the purpose of enabling the apparatus to be adjusted sothat the strokes of the ram D will be performed at more or less frequent intervals and the supply of fuel to the furnace be thereby increased or diminished the said oscillatory arm g has near its outer end a series of holes 9 with one or other of which the lower end 9 of the connecting-rod y can be connected, in accordance with the length of the stroke which is to be imparted to the said arm 9. If said connection be made at a point remote from the axis of said oscillatory arm its ambit of movement will be diminished and the train of Wheels G G G G will be driven by the pawl g at their slowest speed; but if said connection be made at a point closer to the axis of said oscillatory arm then the amplitude of movement of said arm will be augmented and the train of wheels will be driven by said pawl at their greatest speed.

This arrangement, therefore, enables the speed of the cam wheel G4 to be regulated and the opening and closing of the steam-ports controlled, as required.

The aforesaid ram or pusher D is made of sufficient length to enable it to close the lower end of the hopper. E as it advances in performing a feed-stroke, so as to prevent the fuel. from escaping from the said hopper and getting behind the ram or pusher.

We do not wish to confine ourselves to the arran gement of gearing above described for actuating the cam-wheel and the steam-valve. For instance, in Figs. 4 to 6 we have illustrated a modified construction wherein the train of gear-wheels is dispensed with and wherein motion is imparted to the slide-valve from an auxiliary engine H, specially provided for working said slide-valve. The auxiliary engine here shown comprises a steamcylinder of the oscillatory type furnished with trunnions mounted in bearings H H, suitable ports being formed in the said bearings and trunnions for the purpose of permitting live steamto enter said cylinder and exhaust-steam to escape therefrom, as is well understoodin this class of engine. The piston is connected by a rod H to a crank-disk H which is mounted on the shaft of a worm h, gearing with a worm-wheel h. This wormwheel is connected by a rod 71.2 with one end of a bent lever 71 pivoted to the oscillatory arm g This arm has a pawl g engaging with ratchet-teeth on the periphery of the camwheel which operates the roller or projection 0 for actuating the slide-valve O in an analogous manner to that already described. The free end of the said bent lever its is adapted to strike against an adjustable stop 70", which is mounted upon a segmental piece 7L5, fixed to the oscillatory arm g As the wormwheel h revolves in the direction represented by the arrow in Fig. 4 motion will be imparted to the rod 71. and the bent lever h and 'when the free end of the latter meets the the continued movement of the worm-wheel h and rod 71 be caused to perform a feeding stroke and move the ratchet-wheel G, the extent of this movement being increased or diminished in accordance with the position the adjustable stop it occupies on the segmental piece 715'. A step-by-step movement is thus imparted to the said ratchet or cam wheel G Instead of arranging the adjustable stops d cl on a sliding bar d' we arrange them upon a rocking bar pivotally connected at (1 to some stationary part of the apparatus. The said rocking bar is provided with a crosspiece carrying the two pawls d and d, which gear with the ratchet-teeth of the said cam-wheel Gr in opposite directions, so that as the said rocking bar rocks in one direction the pawl d will drive the cam-wheel G, while the other pawl (1 remains inactive; and when the said rocking bar rocks in the opposite direction thepawl (1 will drive the said cam-wheel Gr and the pawl d will remain inactive. The rocking movements of the said bar are efiectedby means of the roller cl, mounted on the depending arm (I of the ram D, and the abutinents d 61 on the rocking bar have inclined under surfaces al with which the roller cZ engages as the said ram reciprocates. The position of these abuts ments on the rocking bar regulates the times in the stroke of the piston and ram at which the steam to the cylinder will be cut on? in an analogous manner to that already described with reference to Figs. 1 to 3.

What we claim, and desire to secure by Letters Patent of the United States, is

1. In a mechanical stoker, the combination with a fluid-pressure cylinder, a ram worked thereby for supplying to the furnace the charges of fuel, and a valve for controlling the passage of the pressure fluid to and from said cylinder; of a cam-wheel for actuating the valve, and of means for imparting astepby-step motion to said cam wl1eel substan tially as and for the purpose specified.

2. In a mechanical stoker, the'combination with the fluid-pressure cylinder, the ram and the valve; of a cam-wheel for actuating the valve, of a pawl-and-ratchet device for imparting motion to said cam-wheel, of mechanical means for driving the pawl-and-ratchet device, and of means for imparting additional motion to said cam-wheel independently of the said pawl-and-ratchet device, substantially as and for the purposespecified.

3. In a mechanical Stoker, the combination with the fluid-pressure cylinder, the ram and the valve; of a cam-wheel for actuating the valve, of a pawl-and-ratchet device for imparting motion to the cam-wheel, of mechanical means for driving the pawl-and-ratchet device, of an arm on the ram, of a movable bar provided with abutments lying in the path of said arm so as to be operated thereby as the said ram terminates its forward and rearward strokes for the purpose of actuating said movable bar, and of means whereby the movements of said bar are transmitted to said cam-wheel substantially as and for the pur pose specified.

4. In a mechanical stoker, the combination with the fluid-pressure cylinder, theram and the valve; of a cam-wheel for actuating the valve, of a pawl-and-ratchet device for imparting motion to the cam-wheel, of mechanical means for driving the pawl-and-ratchet device, of an arm on the ram, of a movable bar provided with adjustable abutments lying in the path of said 'arm so as to be operated thereby as said ram terminates its forward and rearward strokes for the purpose of actuating said movable bar, and of pawls connected with said movable bar and adapted to impart the movements of said bar to said cam-wheel substantially as and for the pur- I pose specified.

5. In a mechanical Stoker, the combination with the fluid-pressure cylinder, the ram and the valve; of a cam-wheel for actuating the valve, of a pawl-and-ratchet device for imparting motion to the cam-wheel, of mechanical means for driving the pawl-and-ratchet device, of an arm on the ram, of a rocking bar provided with adjustable abutments havin g inclined surfaces lying in the path of said arm so as to be operated thereby as said ram terminates its forward and rearward strokes for the purpose of actuating said rocking bar,

the valve; of a eamwheel, a sliding bar coni nected with the valve, a projection on said sliding bar engaging with the cam-slot of said cam-wheel, a pawl-and-ratchet device for imparting motion to the cam-Wheel, mechanical means for driving the pawl-and-ratchet device, an arm on the ram, a rocking bar provided with adjustable abutments having inclined surfaces lying in the path of the said arm so as to be operated thereby as said ram terminates its forward and rearward strokes for the purpose of actuating said rockingbar, and two pawls carried by the rocking bar and engaging with the ratchet of the cam-wheel in opposite directions for imparting thereto the rocking movements of said bar substantially as and for the purpose specified.

7. In a mechanical stoker, the combination with the fluid-pressure cylinder the ram and the valve; of a cam-wheel for actuating the valve, of a pawl-and-ratchet device for imparting motion to said cam-wheel, of an oscillatory arm carrying the pawl of said ratchet device, of mechanical means for oscillating &

said arm, and of means for varying the amplitude of the oscillations of said arm for the purpose specified.

8. In a mechanical stoker, the combination with the fluid-pressure cylinder the ram and the valve; of a cam-wheel for actuating the valve, of a pawl-and-ratchet device for imparting motion to said cam-wheel, of an oscillatory arm carrying the pawl of said ratchet device, of a lever pivoted to said oscillatory arm, of a stop-piece adapted to lie in the path of the free end of said lever, and of means for actuating said lever and, through it, the oscillatory arm substantially as and for the purpose specified.

9. In a mechanical stoker, the combination with the fluid-pressure cylinder the ram and the valve; of a cam-wheel for actuating the valve, of a pawl-and-ratchet device for imparting motion to said cam-wheel, of an oscillatory arm carrying the pawl of said ratchet device, of a bent lever pivoted to said oscillatory arm, of an adjustable stop adapted to lie in the path of the free end of said bent lever, of a crank-plate connected by a rod with the opposite end of said bent lever, and of a fluid-pressure motor for driving said crankplate through suitable gearing substantially as and for the purpose specified.

In testimony whereof we have hereunto set our hands, in presence of two subscribing witnesses, this 6th day of January, 1902.

GEOFFREY HOWARD. GEORGE GIBBS.

Witnesses:

JOSEPH WILLISON, T. B. PORTER. 

